(1) Field of the Invention
The invention relates to the fabrication of integrated circuit devices, and more particularly, to a method and apparatus for storing and transportation of components, such as reticles, that are used in semiconductor manufacturing.
(2) Description of the Prior Art
In the art of creating semiconductor devices, it is frequently required to transport these devices from one location in the semiconductor foundry to another location. The same is true for parts of processing tools, such a reticles, which may be required at more than one location. In view of the cost of the parts that are being transported, it is to be expected that extreme care must be taken during transportation, assuring that no damage is incurred by the transported components as a result of the transportation thereof.
Components that may need to be transported include the indicated reticles but can also comprise semiconductor (ceramic, glass, gallium arsenide, sapphire and silicon) substrates, surfaces containing epitaxial layers of silicon supported by a base semiconductor, printed circuit boards, flex circuits, metallized substrates, substrates used for flat panel displays and semiconductor device mounting support.
When transporting semiconductor components, one of the causes of concern is the occurrence of Electro Static Discharge (ESD) or static electricity, which readily develops on surfaces that contain insulating materials since the insulating materials inhibit the free flow of accumulated electrical charges to other, potentially less harmful locations. Any frictional contact or movement that occurs between components containing insulating materials is prone to result in the accumulation of electromagnetic charges. These electromagnetic charges will, at the time that these charges are brought in contact with a conductive path of low resistivity, discharge, potentially causing damage to the components on the surface of which the ESD has accumulated or injury to an individual through whom the discharge may take place.
Strict measures are typically taken to prevent the accumulation of electrical charges by methods of grounding production equipment, by controlling the humidity in the work environment thus preventing the accumulation of electrical charge or by facilitating discharge to ground surfaces by making these surface more conductive and therefore more likely to form a conduit for ongoing electrical discharge during operational activities. As a side benefit of these activities it is typically found that other negative factors in the manufacturing environment, such as the accumulation of dust, is also further controlled and reduced.
When however taking into account the size and the complexity of a typical semiconductor manufacturing facility, in addition to the large number of processing tools that are typically present in such a facility, it is to be expected that the occurrence of the accumulation of random electrical charges as yet remains a problem and that the complete elimination of such charges is an objective that as yet has to be met.
Since however it remains a requirement that semiconductor components, as listed above, must as yet be transported from location to location within a semiconductor foundry, it is good policy to assume that randomly accumulated electrical charges are present and that therefore the components that are being transported must be protected against potential damage from these charges during transportation. For this purpose a container is frequently used into which the component is posited during transportation.
To avoid the above highlighted problems, the container must be constructed such that no electrical charge can affect the component that is loaded into the container. Current containers consist of the body of the container that comprises a top lid, a bottom lid and four sidewalls that extend between the top lid and the bottom lid in a planar perpendicular construction. The top lid, bottom lid and sidewalls define the cavity of the container. The materials that are typically used for the creation of the elements of the container contain electrically insulating materials such as polymeric materials, for reasons that have been detailed above.
With this type of a construction it has however been found that, due to the uniform nature of the elements of the container when viewed in cross section of these elements, electrical charge may as yet accumulate on the elements of the container, charging one or more of the elements of the container and therefore as yet penetrating to the component that is contained inside the container.
It is therefore of value for the process of transporting semiconductor components in a semiconductor manufacturing environment to provide a container such that no electrical charge can penetrate to the component that is transported inside the container. The invention provides such a container by inserting a metallic coating between layers of polymeric materials, a stack of polymeric material and metallic coating is used to create the elements (such as a top lid, a bottom lid and sidewalls) of the container.
U.S. Pat. No. 6,196,391 (Li) and U.S. Pat No. 5,999,397 (Chen et al.) show containers for ESD protection of reticles.
U.S. Pat. No. 5,469,963 (Bonora et al.) is a related patent.
U.S. Pat. No. 4,776,462 (Ksugi et al.) shows a container for a reticle.
A principle objective of the invention is to provide a container that can be used to transport semiconductor components such that these components will not be affected by discharge of static electricity.
It is another objective of the invention is to provide a method and package for handling a photolithographic reticle.
Another objective of the invention is to provide a method and package that prevents the occurrence of ESD on a photolithographic reticle.
In accordance with the objectives of the invention, a new container is provided whereby an article that is stored inside the cavity of a container will not be affected by a discharge of static electricity. The article stored in the container is protected against electromagnetic charges that accumulate as a result of the triboelectricity mechanism and charges that are induced by an electromagnetic field. A compound material is used for the creation of the container, the compound material contains a metallic material that is wedged between layers of polyimide material. The layering of materials effectively shields the component that is loaded into the container against surrounding electromagnetic fields.